FUNDAMENTALS OF COMPUTER

Detailed explanation-1: -6. The output of the is not sorted in the Mapreduce framework for Hadoop. Explanation: The output of the reduce task is typically written to the FileSystem. The output of the Reducer is not sorted.

Detailed explanation-2: -Hadoop MapReduce is a software framework for easily writing applications which process vast amounts of data (multi-terabyte data-sets) in-parallel on large clusters (thousands of nodes) of commodity hardware in a reliable, fault-tolerant manner.

Detailed explanation-3: -Sort phase in MapReduce covers the merging and sorting of map outputs. Data from the mapper are grouped by the key, split among reducers and sorted by the key. Every reducer obtains all values associated with the same key. Shuffle and sort phase in Hadoop occur simultaneously and are done by the MapReduce framework.

Detailed explanation-4: -MapReduce default Hadoop reducer Output Format is TextOutputFormat, which writes (key, value) pairs on individual lines of text files and its keys and values can be of any type since TextOutputFormat turns them to string by calling toString() on them.

Detailed explanation-5: -The intermediate key value data of the mapper output will be stored on local file system of the mapper nodes.